diff --git a/.github/workflows/code.yml b/.github/workflows/code.yml
new file mode 100644
index 00000000..b5b5b0bc
--- /dev/null
+++ b/.github/workflows/code.yml
@@ -0,0 +1,111 @@
+name: Unit Tests & Code Coverage
+
+on:
+  # Triggers the workflow on push or pull request events but only for the main branch
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+  workflow_dispatch: # allow manual triggering
+
+defaults:
+  run:
+    shell: bash -l {0}
+
+jobs:
+  lint:
+    name: Code style
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout the repository
+        uses: actions/checkout@v4
+
+      # TODO:
+      # - uses: actions/setup-python@v5
+      #   with:
+      #     python-version: "3.12"
+
+      # - name: Run ruff
+      #   uses: davidslusser/actions_python_ruff@v1.0.1
+      #   with:
+      #     python_version: "3.12"
+
+  tests:
+    name: Python ${{ matrix.python-version }}
+    runs-on: ubuntu-latest
+    needs: lint
+    strategy:
+      matrix:
+        python-version:
+          # - "3.13"  # not yet
+          - "3.12"
+          - "3.11"
+          - "3.10"
+          - "3.9"
+          - "3.8"
+      max-parallel: 5
+    env:
+      DISPLAY: ":99.0"
+
+    steps:
+      - name: Checkout the repository
+        uses: actions/checkout@v4
+
+      - name: Set timezone
+        uses: szenius/set-timezone@v2.0
+        with:
+          timezoneLinux: "America/Chicago"
+
+      - name: Install OS libraries to test Linux PyQt apps
+        run: |
+          sudo apt update -y
+          sudo apt install -y \
+            libxcb-icccm4 \
+            libxcb-image0 \
+            libxcb-keysyms1 \
+            libxcb-randr0 \
+            libxcb-render-util0 \
+            libxcb-xinerama0 \
+            libxcb-xfixes0 \
+            libxkbcommon-x11-0 \
+            x11-utils \
+            xvfb
+
+      - name: Create Python ${{ matrix.python-version }} environment
+        uses: mamba-org/setup-micromamba@v1
+        with:
+          cache-environment: true
+          cache-environment-key: env-key-${{ matrix.python-version }}
+          condarc: |
+            channel-priority: flexible
+          environment-file: env.yml
+          environment-name: anaconda-test-env-py-${{ matrix.python-version }}
+          create-args: >-
+            coveralls
+            pytest
+            pytest-cov
+            pytest-qt
+            pytest-xvfb
+            python=${{ matrix.python-version }}
+            setuptools-scm
+
+      - name: Initial diagnostics
+        run: |
+          micromamba info
+          micromamba list
+          conda config --show-sources
+          conda config --show
+          micromamba env list
+          printenv | sort
+
+      - name: Install this package
+        shell: bash -l {0}
+        run: pip install --no-deps -e .
+
+      - name: Run tests with pytest
+        shell: bash -l {0}
+        run: |
+          xvfb-run pytest -vvv .
diff --git a/.github/workflows/pypi.yml b/.github/workflows/pypi.yml
new file mode 100644
index 00000000..0c225569
--- /dev/null
+++ b/.github/workflows/pypi.yml
@@ -0,0 +1,56 @@
+name: Publish Python 🐍 distributions 📦 to PyPI and TestPyPI
+
+on:
+  # Triggers the workflow on push events but only for the main branch
+  push:
+    branches:
+      - main
+    tags:
+      - "*" # all tags
+
+jobs:
+  pypi:
+    name: Build and publish Python 🐍 distributions 📦 to PyPI and TestPyPI
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout this project
+        uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.11"
+
+      - name: Install pypa/build
+        run: >-
+          python -m
+          pip install
+          build
+          --user
+      - name: Build a binary wheel and a source tarball
+        run: >-
+          python -m
+          build
+          --sdist
+          --wheel
+          --outdir dist/
+          .
+
+      - name: Install twine
+        run: >-
+          python -m
+          pip install
+          twine
+
+      - name: Check package metadata
+        run: >-
+          twine check dist/*
+
+      - name: Publish distribution 📦 to PyPI
+        if: startsWith(github.ref, 'refs/tags')
+        uses: pypa/gh-action-pypi-publish@release/v1
+        with:
+          user: __token__
+          password: ${{ secrets.PYPI_API_TOKEN }}
+          verbose: true
diff --git a/mdaviz/tests/__init__.py b/mdaviz/tests/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/mdaviz/tests/test_aboutdialog.py b/mdaviz/tests/test_aboutdialog.py
new file mode 100644
index 00000000..6b41e99e
--- /dev/null
+++ b/mdaviz/tests/test_aboutdialog.py
@@ -0,0 +1,20 @@
+from PyQt5 import QtWidgets
+
+from .. import aboutdialog
+
+
+def test_about_starts(qtbot):
+    """About dialog should start with no errors."""
+
+    class SetStatusWidget(QtWidgets.QWidget):
+        """Test class with setStatus() method."""
+
+        def setStatus(self, status):
+            pass
+
+    fake_main_window = SetStatusWidget()
+
+    dialog = aboutdialog.AboutDialog(fake_main_window)
+    qtbot.addWidget(dialog)
+    dialog.show()
+    assert dialog is not None
diff --git a/mdaviz/tests/test_app.py b/mdaviz/tests/test_app.py
new file mode 100644
index 00000000..4e51148e
--- /dev/null
+++ b/mdaviz/tests/test_app.py
@@ -0,0 +1,26 @@
+from contextlib import nullcontext as does_not_raise
+
+# TODO: (below) from PyQt5 import QtWidgets
+
+from ..mainwindow import MainWindow
+
+# FIXME: gui starts and waits for user to close it
+# def test_app(qtbot):
+#     """mdaviz app should start with no errors."""
+#     from .. import app
+
+#     gui = app.gui()
+#     assert gui is not None
+
+
+def test_app_startup(qtbot):
+    """Repeat the steps here that start the GUI, don't wait for user."""
+    with does_not_raise():
+        # FIXME: dumps core
+        # app = QtWidgets.QApplication([])
+        # assert app is not None
+
+        main_window = MainWindow()
+        assert main_window is not None
+        # main_window.setStatus("Application started ...")
+        # main_window.show()